This project is a continuing program to advance understanding of neural mechanisms of learning and memory by the combined use of behavioral, neurochemical and neuroanatomical methods. Three related directions of research are proposed: (a) Study effects of formal training on chemical and anatomical brain measures in rats and compare these effects with those already found as consequences of differential informal experience. We have already obtained some evidence of cerebral effects of formal training and propose now to concentrate on anatomical measures such as dendritic branching and dendritic spine counts. These cerebral changes are likely to be achieved in part through protein synthesis which is taken up in objective b. (b) Test a model of memory storage by performing experiments on brain biochemistry and memory in mice, using drugs to evaluate the roles of RNA, protein sysnthesis and arousal in memory storage and retrieval. Conduct related biochemical tests of effects of inhibition of protein synthesis on catecholamines and other neurotransmitters. Directions a and b should yield increased knowledge of the structural alterations and chemical processes involved in memory; such knowledge will affect further research and should eventually lead to applications related to health and education. (c) Study how differential experience can counteract the effects of brain lesions and other kinds of brain damage. We have found beneficial effects of enriched postlesion experience, but a fuller understanding of the mechanisms will require both parametric variation of certain aspects of the experience and also detailed chemical and anatomical study of the brains. As well as helping to illuminate aspects of brain plasticity, this research is likely to have applied value in providing a model that will be useful in designing clinical research on recovery of function in human beings.